Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYalnız künye2026Machine learning-based multi-class classification of rock mass permeability using integrated geotechnical and geophysical parameters
Sari, Mahmut; Alemdag, Selcuk; Melek, Mesut; Seren, Aysel
In engineering applications, machine learning (ML) provides a promising approach when direct characterization of subsurface properties is challenging, time-consuming, and costly. This study developed a multi-class ML framework for classifying rock mass permeability based on Lugeon values using 86 observations from drilling and geophysical investigations at the Kırklartepe dam site in Bayburt, Türkiye. Seven predictors were considered: depth, Rock Quality Designation (RQD), joint frequency, Schmidt hammer hardness, P-wave velocity, S-wave velocity, and electrical resistivity. The observations were assigned to four permeability classes: very low, low, moderate, and high. Six classifiers were evaluated: Polynomial Kernel Support Vector Machine (P-SVM), Linear Discriminant Analysis, k-Nearest Neighbors (k-NN), AdaBoostM2, Bagged Trees, and Radial Basis Function SVM. Sequential Forward Feature Selection and Leave-One-Out Cross-Validation were used for feature selection and model evaluation, respectively. Robustness was further assessed using bootstrap confidence intervals, class-imbalance treatments, feature-selection stability, and learning curves. Among the baseline models, P-SVM using all seven predictors achieved the highest accuracy (79.07%), with a macro-F1 of 0.774 and the lowest Golden Distance (GD = 0.4372). When balanced class-wise performance was prioritized, k-NN with in-fold SMOTE achieved the lowest overall GD (0.4126) and a macro-F1 of 0.777. S-wave velocity and electrical resistivity were the most influential predictors. Overall, the findings demonstrate that the proposed framework effectively integrates geotechnical and geophysical data for rock mass permeability classification, providing a robust, data-driven decision-support approach that supports subsurface characterization and complements conventional permeability assessment in engineering applications.
- MakaleYayıncıda açık erişim2025Discontinuity characterization for slope stability assessment using combined aerial photogrammetry, and geophysics approach
Junaid, Muhammad; Abdullah, Rini Asnida; Ullah, Arshad; Sa’ari, Radzuan; Mahmood, Sajid; Rehman, Hafeezur; Rehman, Safi ur; Sari, Mahmut
An expeditious and precise slope stability assessment approach is required to mitigate the personnel and economic losses due slope failure disaster. This study successfully determines various discontinuity properties such as degree of fracturing, discontinuities orientation and persistence using combine unmanned aerial vehicle (UAV) and 2D electrical resistivity tomography (2D ERT) to evaluate the stability of the slope. The discontinuity orientations govern the various modes of failure such as planar, wedge, and flexure toppling. Whereas the degree of fracturing of the rock mass evaluates the quality of the rock mass using Rock Quality Designation (RQD) index. In addition, the persistence is defined as the extent to which the discontinuity on exposed surface rock intruded inside the rock mass. The 3D point cloud from UAV images allows to obtain the discontinuity orientations to analyse the potential failure at the site. The upper portion of the slope has no risk of planar and wedge failure, whereas 20% of the discontinuities are favourable for flexure toppling. In contrast, at the lower section of the slope 1.04%, 4.86% and 20% discontinuities are prone to planar, wedge and flexure failure respectively. At the same time the RQD index obtained via UAV survey reveals that the respectively area covered by very poor, poor, fair, good, and excellent rock were 7 m2, 3904 m2, 38,775 m2, 42,943 m2, 1546 m2. The ERT survey enable to estimate the area covered by poor, fair, good and excellent rock were 4 m2, 1650 m2, 2592 m2, 27,729 m2, and 55,200 m2, respectively. Both the UAV and 2D ERT survey shows the poor-quality rock in the north-east of the slope that reveals that the discontinuities are extended inside the rock mas. This study, therefore, conclude that the combined 2D ERT and UAV approach is efficient and expeditious approach for comprehensive slope stability assessment.
- DüzeltmeAçık Erişim2025Discontinuity characterization for slope stability assessment using combined aerial photogrammetry, and geophysics approach (Oct, 10.1007/s11069-024-06932-3, 2024)
Junaid, Muhammad; Abdullah, Rini Asnida; Ullah, Arshad; Sa'ari, Radzuan; Mahmood, Sajid; Rehman, Hafeezur; Rehman, Safi ur; Sari, Mahmut
In this article the author’s name Mahmut Sari was incorrectly written as Mahmut Saari. The original article has been corrected.
- MakaleAçık Erişim2024Gümüşhane ilinde deprem ivme ve manyetik alan istasyonlarının kurulumu ve işletilmesi
Öztürk, Serkan; Maden, Nafiz; Beker, Yasemin; Sari, Mahmut; Pehlivan, Levent
Bu çalışmada, Kuzey Anadolu Fay Zonu (KAFZ) üzerinde meydana gelen bir depremden Gümüşhane ilinin etkilenme derecesini belirlemek üzere deprem ivme kayıt cihazlarının yerleştirilmesi ve Güneşte meydana gelen fırtınalar nedeniyle yer Manyetik alanındaki değişimleri gözlemlemek amacıyla 3 bileşen Flux-Gate manyetometrenin kurulumu amaçlanmıştır. Deprem ivme kayıt cihazlarının (3 adet); Gümüşhane ili için önem taşıyan Karaca Mağarası ve Kürtün hidroelektrik santrali ile KAFZ’na yakınlığından dolayı Şiran MYO’na kurulması uygun görülmüştür. Flux-gate Manyetometresi ise Gümüşhane Merkez ilçede kurulmuştur. KAFZ üzerinde meydana gelen bir depremden Kelkit, Şiran ve Köse ilçeleri daha çok etkilenirken Torul ve Kürtün ilçeleri daha az etkilenmektedir. Gümüşhane’nin 17 km kuzeybatısında yer alan Karaca Mağarası bölgemizin önemli turizm merkezlerinden birisidir. Kürtün ilçesinde, Harşit nehri üzerinde kurulu olan Kürtün Hidroelektrik santrali enerji amaçlı olarak hizmet vermesi yanında baraj gölü üzerinde balık üretimine ve su sporları yapılmasına imkân sunmaktadır. Güneşte aniden gelişen çok şiddetli patlamalar dünyaya ulaştıklarında elektrik ve iletişim hatlarını kesilebilmekte, radyo haberleşmesinde bozulmalara ve radyasyona sebep olmaktadır. Gümüşhane kurşun, çinko, bakır, altın ve gümüş gibi değerli metaller açısından oldukça yüksek bir potansiyele sahiptir. Bu tür maden yataklarının belirlenmesinde Jeofizik yöntemlerden bir tanesi olan Manyetik yöntem oldukça başarılı bir şekilde kullanılmaktadır. Bu yöntemde arazide ölçü alınırken yer manyetik alanının sürekli kaydedilmesine hizmet edecektir.
- MakaleAçık Erişim2024Geophysical and numerical approaches to solving the mechanisms of landslides triggered by earthquakes: A case study of Kahramanmaraş (6 February, 2023)
Sari, Mahmut
Many landslides occurred in the 11 Turkish provinces affected by the earthquakes centered in Kahramanmaraş in February 2023, and many people lost their lives due to those landslides. To reduce the risks and hazards brought on by landslides induced by earthquakes, it is essential to identify the mechanisms causing landslides to arise in such situations. In this study, the geological strength index and both seismic refraction tomography and electrical resistivity tomography (ERT) geophysical methods were used to determine the failure mechanism of layered sedimentary units defined as flysch (claystone-siltstone-sandstone-marl). The shear strength reduction finite element method (SSR-FEM) was used with the RS2 computer program for model solutions. One of the geophysical methods, ERT, facilitated an interpretation of the cyclic failure mechanism that occurs in flysch, and it was found to be congruent with numerical models. Landslide slip circle depth, water-saturated layers, and resistivity values were determined with the ERT method. Seismic methods were employed to determine the velocity values (Vp, Vs) of the landslip mass. These velocity data, along with the elasticity modulus and Poisson ratios derived from them, were utilized in our numerical model. In the maximum shear strength and horizontal displacement analyses performed on the section line determined before the landslide, the natural state and the situation under the influence of groundwater were examined and the strength reduction factor (SRF) was determined as 1.35 and 1.24, respectively. In an evaluation conducted under the influence of the maximum horizontal ground acceleration (0.22 g) determined by taking into account the seismicity of the study area, it was concluded that instability occurred in the flysches and the SRF value was 0.72. An important finding of this study is that the results of geophysical methods used to determine the lithological properties of sedimentary rock masses and understand the causes of landslides align closely with those of numerical analysis methods, providing high accuracy. These methods also support new approaches, particularly in identifying landslip boundaries and detecting areas with high water saturation. It has been discovered that earthquakes actively contribute to the instability of these kinds of soils.
- MakaleAçık Erişim2023Detection of buried objects with different material properties by ground penetrating radar (GPR) method; [Farklı malzeme özelliklerine sahip gömülü nesnelerin yer radarı (GPR) yöntemiyle tespit edilmesi]
Sari, Mahmut
GPR which permits the capture of high-resolution subterranean data, has developed into a key geophysical technique for determining the depth, geometry, boundaries, and volumes of buried shallow objects. In this study, the detectability of the location, size, and physical property parameters of buried objects with the ground radar method was reveal ed by creating a laboratory environment in real field conditions. For this purpose, a realistic laboratory environment with a depth and length of 5 m was created on the filled soil material at the test site, and buried objects with different material properties were placed. In addition, by adding sand material to the middle part of the soil fill material in the test area, its situation in different layers was tried to be examined. GPR data were collected on the models using the RAMAC CU II system and a 500 MHz center frequency shield antenna. After processing the data, reflected/scattered electromagnetic (EM) wave fields on the radargram of a profile perpendicular to the buried objects were examined. In this way, the positions, sizes, physical properties (types) of buried objects along with their depths and their situations in different layer environments have been revealed. According to the results, the peak width of hyperbolas and the sizes of buried objects were determined on the processed radargrams. The types of buried objects and their situations in different layer environments are clearly revealed. The scattered wave field amplitudes of the plastic pipe (A and C regions) from the reflection coefficients are substantially lower than the scattered wave field amplitudes of the iron pipe (B region) from the buried objects. It is thought that the strong reflections extending from the C region to the deep on the radar are caused by the lead blocks in the plastic pipe.
- MakaleAçık Erişim2023Evaluation of stability in rock-fill dams by numerical analysis methods: a case study (Gümüşhane-Midi Dam, Türkiye)
Sari, Mahmut
Serious stability issues could arise both during and after construction if the dams’ body designs are not realistically accurate. Engineering studies are therefore crucial for identifying the body’s instability prop-erties in designing the dam body. In this study, horizontal and vertical displacement and stress-deformation analyses were carried out on the body of the Midi Waste Dam located in Karamustafa Village of Gümüşhane Province. In these analyses, the elasticity modulus and Poisson’s ratio of the soil were determined using the seismic method, which is one of the commonly used geophysical methods. The cohesion and internal friction angle of the rock fill were determined by taking into account Leps’ charts. The state of the dam body under the influence of the siltation load and seismic load at the end of operation was shown by applying the finite element method. It was found that there was no instability issue with the researched dam because the safety numbers obtained from the stability study of the dam body were greater than the 1.2 safety number accepted for the stability of the dams (SRF: 2.03, SRF: 1.37). The maximum vertical displacement of the dam body at the foundation base was found as 3.78 cm, the horizontal displacement as 5.80 cm, and the total displacement amount as 6.75 cm when the dam body was examined in terms of displacements. In terms of the statics of the dam body, the vertical, horizontal, and total displacements estimated with the numerical analysis methods did not present a problem, and it was demonstrated that this scenario was also supported by the stability of the body in the applied analyses.
- MakaleAçık Erişim2022Determination of rock quality designation (RQD) in metamorphic rocks: a case study (Bayburt-Kırklartepe Dam)
Alemdag, Selcuk; Sari, Mahmut; Seren, Aysel
The role and importance of rock mass classification systems from past to present in engineering designs are indisputable. Therefore, the correct estimation of the parameters that make up these systems is essential in terms of reliability, time, and economy. One of the crucial parameters commonly used in rock mass classification is the rock quality designation (RQD). This study aimed to indirectly estimate the RQD value determined from the core samples obtained from the exploration drillings. In this context, P wave velocity (Vp) was obtained by seismic refraction tomography (SRT) from the geophysical measurements applied in the metamorphic rock mass, and the discontinuity frequency parameter was obtained from the line survey studies carried out on the rock mass. What determined RQD values with the help of simple regression analyzes and empirical equations with high estimation capacity using Vp and discontinuity frequency parameters were obtained without drilling in the rock mass. Accordingly, the performance indexes of the equations produced by different researchers and the equations produced in this study were evaluated in determining the RQD parameter. In the generated equations, the highest coefficient of determination value depending on joint frequency and Vp wave velocity with RQD was calculated as R2 = 0.89 and R2 = 0.82, respectively. When the produced equations are evaluated according to the performance indexes, it is seen that the empirical equations obtained by previous studies have the highest root mean square error (RMSE) and values account for (VAF) values compared to the other equations and have very high estimation capacities. Thanks to the equations with high estimation capacity, the RQD value was determined depending on the joint density and Vp speeds.
- MakaleYalnız künye20223D Modelling and Feasibility Assessment of Granite Deposit using 2D Electrical Resistivity Tomography, Borehole, and Unmanned Aerial Vehicle Survey
Junaid, Muhammad; Abdullah, Rini Asnida; Sa’ari, Radzuan; Ali, Wahid; Islam, Amber; Sari, Mahmut
This research work aims to critically analyze the efficacy of inexpensive and rapid 2D electrical resistivity tomography (2D ERT) survey for sub-surface geological delineation of granite deposits. The research work involves six ERT profiles using the Schlumberger protocol with an inner and outer electrode spacing of 5 m and 10 m, respectively. In addition, the unmanned aerial vehicle (UAV) survey is also performed to obtain the terrain information of the studied area. At the same time, a few boreholes are drilled to validate the 2D ERT interpretations. The 2D ERT survey reveals that strong resistivity contrast enables inverted resistivity imaging to characterize the deposit such as topsoil (100-800 Ωm), fracture granite (800-2300 Ωm), and solid granite (> 2300 Ωm). The results obtained from UAV, 2DERT, and borehole survey are further processed to estimate the bedrock to topsoil ratio to assess the feasibility of the deposit. The bedrock to topsoil ratio, estimated by 2D ERT and borehole, is 3.2 and 2.2, respectively. At the same time, the combined UAV, 2D ERT, and borehole survey calculates the bedrock volume 3.2 times to topsoil. Thus the research work allows us to conclude that 2D ERT is an inexpensive, viable, and efficient technique for sub-surface geological documentation, and helps select appropriate mining methods.
- MakaleAçık Erişim2021Estimation of ground types in different districts of Gümüşhane province based on the ambient vibrations H/V measurements
Öztürk, Serkan; Beker, Yasemin; Sari, Mahmut; Pehlıvan, Levent
In this study, an attempt was made to estimate the ground types for Torul, Kürtün, Kelkit, Şiran and Köse districts of Gümüşhane, Turkey, by analyzing the predominant frequency and H/V ratio from microtremor data through the single station microtremor H/V ratio of Nakamura technique. For all districts, predominant frequencies show a general distribution between 1.36 and 9.84 Hz, H/V ratios between 1.01 and 9.58. According to these variations, three transient zones can be suggested as i) Z1, stiff rock composed of gravel, sand and other soils mainly consisting of tertiary or older layers with period of 0.1 to 0.2s, ii) Z2, sandy gravel, stiff sandy clay, loam or sandy alluvial deposits whose depths are 5m or greater with period of 0.2 to 0.4s, and iii) Z3, standard grounds other than type Z1, Z2 or Z4 (alluvial deposits whose depths are 5m or greater) with period of 0.4 to 0.8s. These r esults s uggest that p redominant period obtained from predominant frequency shows significant changes based on the soil formation, and H/V ratio highly corresponds to these subsurface properties. Soil-structure interaction can also be evaluated by considering these results and possible resonance risk can be investigated for building resonant frequency in these residential districts in the next. Thus, this type of application and evaluation of microtremor data may provide primary and useful information for other geophysical, geological and geotechnical studies such as planning the seismic resistant infrastructure, detecting the small-scale seismic risks and making a suitable and reliable seismic hazard microzonation in Gümüşhane. Copyright 2021, Yıldız Technical University.
- MakaleYalnız künye2020Determination of geological structures by geophysical and geotechnical techniques in Kırklartepe Dam Site (Turkey)
Sari, Mahmut; Seren, Aysel; Alemdag, Selcuk
In foundation research of engineering structures, application of geophysics methods before drilling work allows not only more economical studies but also a more detailed determination of underground sections. Especially in pre-feasibility studies on long tunnel routes, dam sites and lake areas, it has a vital importance in terms of structural safety to determine possible underground buried fault lines, lithology changes, anticlinal-synclinal structures and underground openings. By considering these effective factors, the alluvium/bedrock border and the positions of potential buried faults in the dam site and lake area in the Kırklartepe area of the province of Bayburt in northeastern Turkey were determined by comparison with geophysical and geotechnical methods. First of all, the resistivity of the dam axis location and the change of the Vp wave velocity by depth were determined by comparing the results between geophysical methods of electrical resistivity tomography (ERT) and seismic refraction tomography (SRT), respectively. Afterwards, from the foundation boreholes opened in the dam axis location, joint frequency and the other parameters determined by observations were obtained. With these parameters, 2-dimensional zoning profiles of the dam axis location were formed, and the alluvium-bedrock border and the locations of the buried faults were determined. Two potential faults in the NW-SE direction relative to the location of the dam axis were clearly revealed in the zoning profiles obtained in the ERT and SRT measurements. Additionally, the presence of these faults was determined as a result of examining the separation and joint frequency parameters from the drilling core samples collected from the BH_3 and BH_5 boreholes opened in the investigated area based on changes in the vertical and horizontal directions. In addition to these, in the ERT study, two potential faults other than the determined two were also detected. It was seen in the zoning profiles that these faults corresponded to right under the BH_2 borehole and 60 m SW of the BH_6 drilling. Consequently, in the zoning studies conducted at the examined site, the change in the lithology at the dam axis by depth (alluvium-bedrock border), lateral correlations of boreholes and potential faults were determined. It was recommended for the selected dam axis location to be constructed at a more suitable place in the NW direction in terms of engineering. Furthermore, with this study, it was revealed once again that it is highly essential to use geophysical and geotechnical together in conceptualizing large engineering structure projects.
- MakaleYalnız künye2018EMPIRICAL RELATIONS AMONG THE PARAMETERS ASSOCIATED WITH EARTHQUAKE RUPTURE MECHANISMS FOR IRANIAN EARTHQUAKES
Öztürk, Serkan; Ghassemi, Mohammad Reza; Sari, Mahmut
In this study, we aimed to derive the new and more reliable empirical relationships among different seismic parameters associated with the earthquake rupture mechanisms for Iranian earthquakes. For this purpose, we firstly converted the surface wave magnitudes into moment magnitudes in order to prepare a uniform earthquake dataset. Thereafter, we estimated the empirical relationships between moment magnitude and surface rupture length, moment magnitude and maximum displacement, and surface rupture length and maximum displacement. These linear empirical equations were obtained by orthogonal regression and the goodness of fits were discussed in terms of the correlation coefficients. The results obtained by the orthogonal regression in this paper are compared with the results obtained by the least square method in the literature. The present study confirms that representations of statistical correlations among different earthquake faulting parameters can be given more clear and straightforward by the orthogonal regression as compared to the least square method. In addition, such kind of relationships may provide some significant insights for the calculation of the maximum surface rupture length, maximum surface displacement, and associated maximum credible earthquakes for different seismotectonic regions of Iran as well as the estimation of earthquake magnitudes in paleoseismological studies.
- MakaleYalnız künye2018DETECTION OF THE COMPLEX GROUND PROBLEMS BY GROUND PENETRATING RADAR: EXAMPLES FROM GUMUSHANE UNIVERSITY
Sari, Mahmut; Öztürk, Serkan
In this study, Ground Penetrating Radar (GPR) technique was used for the detection of i) the reasons of deformations which occur in the field ground of Gumushane University Sport Complex (GUSC), and ii) the congestion in flow pipe of Gumushane University, Engineering and Natural Sciences Faculty (GUENSF). GPR data was collected by using the RAMAC CU II device and a shielded antenna with a 500 MHz center frequency. The wave fields for GUSC were examined by 2D and 3D processing. The large-scaled hyperbolic reflections are in corresponds to the areas where the field ground has deformations. It is considered that these anomaly areas may include a gap or a padding having a large gap and suggested that these damaged areas must be full with hard materials. The large-scaled hyperbolic reflections approximately starts in one-meter depth and reaches three-meters. For GUENSF, the measurements were conducted on the route where the main flow pipe crosses. In GPR sections, hyperbolas with high amplitudes were observed in the zones where flow pipe passes. Information on slope of flow pipe was provided by examining the association of these hyperbolas with the depth, and the clogged zones were detected. It is stated that unclogging the clogged zones of the flow pipe will not fully contribute to the resolution of the problem. Therefore, it is suggested to provide necessary slope to the flow pipe by completely removing and mounting back. These results show that GPR technique is an effective tool to provide a good image and solution for the complex ground problems.